Technology : Attack on video pirates backfires

HOLLYWOOD’S attempts to prevent pirates from copying films from the new
digital video disc have fallen foul of America’s legal restrictions on the
export of encryption technology. The new digital video discs, each carrying a
full-length feature film, were to have been launched in the next three months.
But a combination of the complexity of the antipiracy technology and the legal
problem will delay the launch.

A consortium of 10 electronics and entertainment giants, led by Toshiba,
Thomson, Matsushita and Time Warner, has developed the digital video disc (DVD).
The DVD consortium has promised the Hollywood studios that they will use digital
encryption to stop people pirating copies on blank discs or video tapes.

But, as software companies already know to their cost, the US government
classifies secure encryption as munitions. So without special dispensation, the
export of both video discs and players will be banned.

The encryption is not just designed to prevent piracy, it is also intended to
prevent people in one country watching the film on disc while it is still being
shown on the cinema. Films are often released first in America and the video
discs will often go on sale before the film has finished its run in European
cinemas. The encryption will prevent the export of discs from the US to Europe,
even if the copies have been produced legitimately.

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The encryption splits the world into five regions. Discs intended for one
region are unplayable on equipment sold in the other four. The digital code on
the disc is scrambled, and the video disc player can only unscramble it when two
halves of a digital key come together.

One half of the key is recorded on the disc along with the movie. The user
provides the other half of the key either by entering an authorisation code, or
by inserting a smart card that stores the code. Each of the five regions will
have its own keys.

To prevent unauthorised copying, the keys on the disc will be further
scrambled on their way out of the player. So the keys on a pirate disc will not
“mate” with a user’s keys and the disc will be unplayable.

The details of the system are still being agreed by the consortium’s working
group on copy protection, which talked to 60 electronics and computer companies
about the best way of encrypting the data. The DVD Consortium is now close to
agreeing the details of its key system. The manufacturers will then have to
modify their players to meet the encryption standard.

An extension of the system will also block analogue copying, to prevent
people connecting the analogue output of the video disc player to the input of
an ordinary video recorder. This part of the technology has been developed by
the American company Macrovision.

When the keys unscramble the digital code from a video disc, they will also
add spurious pulses to the analogue video signal, in between the pictures. A
television set ignores these pulses, but they confuse the recording
circuits of a VCR so that it makes a very poor quality copy.

But the DVD Consortium is also talking to lawyers about whether the US
government will classify movie discs and players as munitions and forbid their
export. Frank Carrubba, executive vice-president of Philips, says: “There will
not be a DVD product this year. There are too many issues and problems still to
be solved.”